Most conventional hitches have a pivot point to allow articulation between an implement coupled with a hitch, such as a plow, and a work machine to which the hitch is attached, such as a tractor. In addition to the pivot point, some hitches allow the pivot point to be manually shifted a short distance laterally, i.e., horizontally, with respect to the tractor.
Conventional hitch systems that allow lateral shifting typically operate in two ways. A pivoting wand or other similar device used for row guidance provides the input indicating the desired offset of the hitch. Typically the wand is suspended from the implement, and is dragged along the ground in contact with a row of crops. When the position of the implement changes relative to the row of crops, the angle of the wand changes. As the angle changes, an appropriate offset of the hitch may be made to prevent the implement from overrunning and causing damage to the row of crops.
Alternately, a manual lever, such as a joystick, or a discrete switch, is toggled to trigger movement by the hitch. For example, when an operator is attempting to hook up an implement with the tractor, often the hitch is not properly aligned with the implement. Instead of requiring the operator to re-align the tractor, the operator may simply adjust the lateral position of the hitch. In addition, a manual lever allows the operator to shift the hitch, and any implement connected to it, to one side. This allows for a more precise positioning of the implement during a variety of field operations.
It has been suggested by some that a hitch may be used to provide a positive steering force to assist during turns of the tractor with the implement in the soil. However, no satisfactory system for accomplishing this has been disclosed. Hitches that use row guidance sensors are clearly not suited for this task. These systems control the position of the hitch solely based on the position of the crop rows, and where no crop row is present, provide no guidance. The manual lever could be used to offset the hitch in this situation. The manual lever, however, provides an additional task for the operator to monitor and respond to. Due to the increasing complexity of modern tractors, it is undesirable to provide additional systems that vie for the attention of the operator while the tractor is in motion.